Sutures for cardio-thoracic surgery are known. Typically, such sutures consist of a length of wire terminating in a curved needle. The curved needle is used to pass the suture through and/or around tissue (including bone) to be sutured. The needle is inserted into the tissue on one side of the incision to be closed and brought out on the other side of the incision. The free end of the wire remains outside the incision. After passing it through the tissue, the needle end is removed with wire snips and the two ends of the wire are drawn together to cinch the suture and then twisted tightly to hold the suture in place.
A drawback of this unknown type of suture is that, in many cases, as the incision heals the tissue immediately surrounded by the wire suture recedes from the suture. This frequently occurs in thoracic surgery, wherein the wire suture is passed through or around the sternum. In many cases bone necrosis will occur and the sternum will recede from the suture, with the result that a suture which was tightly cinched at the start will become loose as the sternum recedes from the suture. This reduces the effectiveness of the suture and can cause pain or discomfort to the patient or even instability of the sternum.
Another disadvantage of the known type of suture is that, once it is tightly cinched, it will not yield. To achieve stability with known sutures, it is necessary to tighten the wires of to the maximum tension possible. If the patient coughs persistently, this results in higher tension on the wires and pressure on the sternum as it moves during coughing. This will increase the change of breakage of the sutures at the junction where the wires are twisted. Moreover, the sutures are subject to loosening if the patient is osteoporotic, the sternum could collapse from the pressure.
The number of known sutures required to achieve stability is also higher than need be. Six to eight known sutures are required in most cases. The present invention is intended to reduce that number substantially.
A further drawback of known sutures is that it is impossible to get a quantitative measurement of the tension put on the wires. Thus, it is possible to put the sutures under too much or too little tension for a particular patient.
Known sutures also tend to be unstable when passed around, rather than through, the sternum.
There is a need for a suturing device which will overcome these and other disadvantages.